Telephone system.



H. G. WEBSTER TELEPHONE SYSTEM. APPLICATION FILED FEB. 28, 1903.

Patented Nov. 24, 1908.

a first actuated, their etiiciency is unimpaired UNITED sTA'r s HARRY G. WEBSTER, OF CHICAGO, ILLINOIS,

ATnr orrrcn.

ASSIGNOR TO KELLOGG SWITOIIBOARI) AND TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Nov. 24, 1905.

Application filed February 28, 1903. Serial No. 1%,459.

To rill whom it may concern:

Be it. known that l. l-Iuncv (i. Wnns'rnn, a citizen of the United States of America. and residing at Chicago, in the. county of (ook and State of Illinois, have invented a new and useful Improvement in 'lelephone Systems, of which the following is a specification.

My invention relates to improvements in telephone systems, and more particularly to means for shunting relays in the talking circuit by means of non-inductive shunts, and this without weakening or destroying the etiiciency of such devices.

My invention may be particularly applied to supervisory relays in cord circuits used for looping subscribers lines together for conversation, whereby when the relays are but as soon as energized non-inductive shunts are connected about them. This arrangement permits the passage of voice currents 'aboutthe relays without hindrance therefrom.

My invention is illustrated in the accompanying drawing in which I Figure 1 shows a telephone system embodying my invention, and Fig. 2 represents a modification.

L and I) indicate subscriberslines extending from the respective substations A and B to the central ofiice, where they are fitted with line signals and connecting jacks in the usual manner. At the substations. for example station A. the transn'iitter t and receiver 5 are placed in a bridge Whose normal discontinuity is maintained by means of the hook switch 6. while a condenser 7 and bell 8 are placed in a permanent bridge of the line conductors 2 and 3. This apparatus is intendednierely to typify any suitable substation outfit.

At the central otlice a cut-oti relay R- is provided for the line which normally grounds conductor 2 through one of its springs and connects line conductor 3 through another of its springs with the conductor 9 leading to the line relay R which is joined upon its other side by means of conductor 10 with the live pole of a central and common battery B. The line relay R controls the local circuit of the individual line signal S. The forward contacts of the springs of the cut-off relay R are connected with the switchboard section of the line ex- 5 tending to the answering jack .I and the multiple jacks J and J. The winding of the c||t-oli,relay it is grounded from the sleeve conductor oi said jacks. The operator is provided with a plurality of cord circuits to loop the subscribers together for conversation. and which comprise a plug I and I provided with tip and sleeve contact surfaces adapted to register with the corresponding contact surfaces of the springjacks of the lines. The tip contacts oi the plugs are connected together by flexible strands Z: and I of the cord circuit and the sleeve contacts are joined by the strands s and 5* thereof. The battery 13 has its grounded pole connected through an impedance coil 11 with the tip strands and its live pole connected through its supervisory relay 1' with the sleeve strands. A supervisory relay 1" is interposed in the strand 1 and a similar relay r is interposed in the strand F. T he relay w serves through its normally open contacts to control current to the supervisory signals and S associated with the calling and answering plugs I and P respectively while the individual local circuits of said lamps are controlled through the normal contacts and springs 12 of said supervisory relays r and r".

Cach of the relays '1' and r are provided with additional normally open contacts 13 which are adapted when attracted to include the non-inductive resistances 14C in the circuit in parallel with the winding of the corresponding relay. By this arrangement when the contacts 13 are open the relays 7*? respond in the ordinary manner and with the usual efiiciency to current flowing through them but as soon as actuated the non inductive shunts are connected about them. which permits a free path for the voice currents and at the same time sntiicient current passes through the windings to maintain them actuated. V

The operators outfit is adapted to be connected in a bridge of the cord circuit by means of any suitable listening key, said outfit comprising the receiver 15, secondary winding of the operatorsinduction coil 16 and a coi'idenser 17. The operators transmitter 18 is preferably actuated-from the same battery B. A ringing generator 19 is adapted to be connected with the cord circuit to call the wanted subscriber. and to maintain the cut-off relay actuated during circuit of and extin -uish lam S and also receiver off its hook and completes a path test the condition of the wanted line in the ho-wever, current flows through the supertalking circuit. 'It will be noted that the ringing, the sleeve contact of said l "ionipletes an auxiliary path over conductor 20 and through resistance 21.

In making a call the subscriber takes hls for current over the metallic ne from the battery B and through the line relay R thus closing the local circuit of signal S and lighting the same. In response to the call the operator inserts the plug P in the answering ack J thereof and completes a path for current from thebattery B over the sleeve strand .9 of the cord circuit and through said cut-ofi" relay R to ground. The actuation of the cut-off relay renders the line signal inoperative and completes a metallic line for talking. Current now flows over the metallic line and through the supervisory relay 7 which is energized to open the local circuit of supervisory signal S and prevent its action. As soon as the said relay r operates it connects through its armature 13 the non-inductive shunt 14: to the same, so that the voice currents are not hindered by the impedance of the winding of the relay. The supervisory relay 1' is also actuated to close circuit through the said supervisory signals. Voice currents are prevented from being short circuited through the battery B by the impedance coil 11 and the relay 7. Upon learning the order the calling plug P is employed to usual manner. Upon finding the line idle, the plug is inserted and the ringing key actuated to call the subscriber. After calling the subscriber and before his response cur rent from the battery Bis flowing over the sleeve conductor 8 of the cord circuit and through the winding' of the cut-off relay to ground. The cut-off relay actuates to render the line signal inoperative and the supervisory signal S is also lighted to indicate the fact of the nonresponse of the subscriber to the operator. Upon his response,

visory relay 1' which is actuated to open the to complete the non-inductive shunt about said relay. Conversation can now take place between the subscribers and without hindrance from'theimpedance coil due to the presence of the supervisory relays in the shunt is inoperative at the point of least cfliciency of the relay, but is closed and brought into circuit only when the relay armature is at its point of greatest efiiciency, in consequence of which arrangement the operative relay winding can be made very much higher and the shunt' winding very much lower than in present practice. At the termination of the conversation. and replacement of the receivers upon the hooks i deenergizes the supervisory relays 7' and 1' comes act together to close the non-inductive resistances 14 about both of said relays, and

which non-inductive resistance is preferably of about 3000 ohms resistance' In this modification the relays would necessarily be adjusted to operate on a margin so as to give double supervision. It is apparent that the invention may be applied to any relay in the talking circuit of a telephone line or system, although of particular advantage in connection with supervisory relays.

' Having thus described my invention what I claim as new and desire to secure by Letters Patent is l. In a telephone system, the combination with a suitable source of current, of a relay in the path of voice currents when a connection is established for conversation, a noninductive resistance in a -normallyopen shunt of said relay, adapted to be connected in parallel with the winding of said relay and in the path of talking current by the actuati n of the rela said relay being ada 'i't'e to be maintai ed actuated by current over the telephone line, whereby the talkingcurrents and the direct current from said source are provided with suitable parallel paths during conversation, substantially as described. y

, 2. In a telephone system, the combination with a suitable source of current, of a relay permanently connected in the. metallic line when a connection is established for conversation and being under the control of the subscriber, a non-inductive resistance in a normally-open shunt about the windings of said relay, said shunt being adapted to be connected in parallel with said windings in the path of talking current by the energization of said relay, whereby the talking currents and the direct current from said source are provided with suitable parallel paths during conversation, substantially as described.

3. In a telephone system, the combination with a telephone line, of a cord circuit for connecting the line for conversation, a supervisory relay in the cord circuit, under thecontrol of the subscriber during the connection of the cord circuit with the line, a suitable source of current, a non inductive resistance in a normally-open shunt of said relay, said shunt being adapted to be connected in the path of voice currents the energization of said relay, whereby the impedance of the coils of said relay is removed I from the path for talking current, said 'r'e- 13o lay constituting a parallel path for the control of the supervisory signals, substantially as described.

4. Ina telephone'system, the combination with a telephone-line, of a cord circuit associated therewith for making connections for conversat1on,a supervisory relay in the cord circuit, under the control of the subscriber during the connection of the cord circuit with the line, a signal controlled by said re- .lay, a non-inductive resistance constituting a normally-open shunt about said relay, said resistance being adapted to be connected in parallel with the windings of said relayv when said relay is energized, whereby direct current from [said source finds a path through the winding of said relay and the talking currents are provided with a suitable parallel path throughsaid resistance,

substantially as described] 5. In atelephone system, the combination with a telephone line, of a cord circuit associated therewith, a suitablesource of current, a supervisory relay associated with the cord circuit in a normally-closed circuit, a

non-inductive resistance in a normally-open shunt ofsaid relay, said shunt being adapted to be closed by-said relay when a connection is established for conversation to remove'the impedance of said relay from the path of talking currents, said relay and said shunt providing parallel paths for direct current from said'source over the telephone line and through the subscribers transmitter, substantially asdescribed.

6. In. a telephone system, the combination with a telephone line, of a cord circuit, a

' supervisory relay associated with the cord circuit and under the-control of the subscriber during the connection of the cord circuit with the line and a normally-open shunt about said relay, adapted to be closed when said relay is. actuated to provide a path for scribed. I

7. In a telephone system, the combination I with a telephone line, of a line signal therefor, a cut-ofi. relay for theline, a cord circuit to establish connections therewith for conversation, a source of current associated with cord circuit and line, supervisory relays associated with the cord circu t n the path of direct current from said source, and -act'uated' over the. telephone line to the substation, and means for closing a shunt about both said relays by the actuation thereof to provide a parallel path for talking currents during conversation, substantially aside,- scribed. I

, transmitter.

talking current, substantally as de- 8. In a telephone system, thecombination with a telephone line, of a cord circuit adapted to'be connected therewith for con versation,-a supervisory relay in said cord circuit having its coil normally in series with the telephone-line when a connection has been established therewith, a non-inducti've shunt in open circuit about said relay, said shunt being adapted to be placed in parallel with the coilofthe relay when the subscribers telephone is in position-forconversation, the direct current supply for said telephone line passing through the coil of said relay alone before its actuation and through the coil and its non-inductive shunt in parallel after the actuation of the relay,

substantially as described.

9. In a telephone system, the combination with .a telephone line, of 'a cord circuit adapted to be connected therewith for conversation, a relay having a single actuating coil in the path of current over the telephone 'line to the subscribers station and ashunt for said relay coil adapted to be. included about the relay by its "own energization whereby the entire current in the line is available for the actuation of the relay but whereby only the portion necessary to maintain the actuation flows through its coil after the actuation,substantially as described.-

11. In a telephones adapted to be connected therewith forconversation, a relayassociated with the cord circuit and energized over a path including the substation, said. relay by its actuation placing a non-inductive shunt about its own Winding whereby the voice currents may pass without the obstruction of theimpedance, substantially as described.

Signed by me at Chicago, county of Cook, State of Illinois, this26th day of February HARRYG. WEBSTER. Witnesses:

Ronnnr LEWIS Arms, GAZELLE Bnnnn ystem, the combination with a telephone line, of a cord circuit 

